Filters are already known which consist of a plurality of layers or plies of metal fibers which are sintered together. Sintering is generally done in a furnace or oven under pressure and at a suitably high temperature, care being taken at the same time to provide that a vacuum is present.
A disadvantage of such a process is, however, that this method or process is relatively expensive and frequently, depending on the medium to be filtered, there also exists the problem that arises when the filter plugs or clogs up. Then the filter must either be replaced or cleaned in a costly and/or time-consuming way.